The invention relates to a diaphragm control apparatus for combined use of an electronic flash with a camera, and more particularly, to a diaphragm control apparatus which is uniquely designed for use with a devoted electronic flash.
A photographic camera of the automatic exposure type, such as a programmed EE camera, having the capability to control a diaphragm value automatically in accordance with an output from a photometric circuit is known. When the camera is provided with a manual diaphragm presetting mechanism and is adapted to enable a flash photography utilizing a devoted or a usual electronic flash, a changeover switch may be provided to switch between a normal automatic exposure and a flash photography utilizing a usual electronic flash. Whenever a flash photography is desired utilizing a usual electronic flash, the changeover switch is thrown to a corresponding position. In this instance, a diaphragm value such as F4, F8, for example, is preset in a camera by operating the manual diaphragm mechanism in accordance with a proper diaphragm value or guide number instructed for use with a usual electronic flash. The changeover switch is thrown to a normal position for taking pictures in a normal automatic exposure mode or by a flash photography utilizing a devoted electronic flash. During a normal automatic exposure mode, a proper diaphragm value is automatically established in response to an output from a photometric circuit, and during a flash photography utilizing a devoted electronic flash, a proper diaphragm value associated with the devoted electronic flash is also automatically established.
However, with a camera of the type described, if a flash photography is attempted utilizing the devoted electronic flash while maintaining the changeover switch thrown to the usual electronic flash position, there results a difficulty that a diaphragm value corresponding to the devoted electronic flash is not established in the camera since a signal from the switch predominates.